#include "cache.h"
#include "dir.h"
#include "pathspec.h"

/*
 * Finds which of the given pathspecs match items in the index.
 *
 * For each pathspec, sets the corresponding entry in the seen[] array
 * (which should be specs items long, i.e. the same size as pathspec)
 * to the nature of the "closest" (i.e. most specific) match found for
 * that pathspec in the index, if it was a closer type of match than
 * the existing entry.  As an optimization, matching is skipped
 * altogether if seen[] already only contains non-zero entries.
 *
 * If seen[] has not already been written to, it may make sense
 * to use find_pathspecs_matching_against_index() instead.
 */
void add_pathspec_matches_against_index(const struct pathspec *pathspec,
                                        char *seen)
{
        int num_unmatched = 0, i;

        /*
         * Since we are walking the index as if we were walking the directory,
         * we have to mark the matched pathspec as seen; otherwise we will
         * mistakenly think that the user gave a pathspec that did not match
         * anything.
         */
        for (i = 0; i < pathspec->nr; i++)
                if (!seen[i])
                        num_unmatched++;
        if (!num_unmatched)
                return;
        for (i = 0; i < active_nr; i++) {
                struct cache_entry *ce = active_cache[i];
                match_pathspec_depth(pathspec, ce->name, ce_namelen(ce), 0, seen);
        }
}

/*
 * Finds which of the given pathspecs match items in the index.
 *
 * This is a one-shot wrapper around add_pathspec_matches_against_index()
 * which allocates, populates, and returns a seen[] array indicating the
 * nature of the "closest" (i.e. most specific) matches which each of the
 * given pathspecs achieves against all items in the index.
 */
char *find_pathspecs_matching_against_index(const struct pathspec *pathspec)
{
        char *seen = xcalloc(pathspec->nr, 1);
        add_pathspec_matches_against_index(pathspec, seen);
        return seen;
}

/*
 * Magic pathspec
 *
 * Possible future magic semantics include stuff like:
 *
 *      { PATHSPEC_NOGLOB, '!', "noglob" },
 *      { PATHSPEC_ICASE, '\0', "icase" },
 *      { PATHSPEC_RECURSIVE, '*', "recursive" },
 *      { PATHSPEC_REGEXP, '\0', "regexp" },
 *
 */

static struct pathspec_magic {
        unsigned bit;
        char mnemonic; /* this cannot be ':'! */
        const char *name;
} pathspec_magic[] = {
        { PATHSPEC_FROMTOP, '/', "top" },
};

/*
 * Take an element of a pathspec and check for magic signatures.
 * Append the result to the prefix. Return the magic bitmap.
 *
 * For now, we only parse the syntax and throw out anything other than
 * "top" magic.
 *
 * NEEDSWORK: This needs to be rewritten when we start migrating
 * get_pathspec() users to use the "struct pathspec" interface.  For
 * example, a pathspec element may be marked as case-insensitive, but
 * the prefix part must always match literally, and a single stupid
 * string cannot express such a case.
 */
static unsigned prefix_pathspec(struct pathspec_item *item,
                                unsigned *p_short_magic,
                                const char **raw, unsigned flags,
                                const char *prefix, int prefixlen,
                                const char *elt)
{
        unsigned magic = 0, short_magic = 0;
        const char *copyfrom = elt, *long_magic_end = NULL;
        char *match;
        int i, pathspec_prefix = -1;

        if (elt[0] != ':') {
                ; /* nothing to do */
        } else if (elt[1] == '(') {
                /* longhand */
                const char *nextat;
                for (copyfrom = elt + 2;
                     *copyfrom && *copyfrom != ')';
                     copyfrom = nextat) {
                        size_t len = strcspn(copyfrom, ",)");
                        if (copyfrom[len] == ',')
                                nextat = copyfrom + len + 1;
                        else
                                /* handle ')' and '\0' */
                                nextat = copyfrom + len;
                        if (!len)
                                continue;
                        for (i = 0; i < ARRAY_SIZE(pathspec_magic); i++) {
                                if (strlen(pathspec_magic[i].name) == len &&
                                    !strncmp(pathspec_magic[i].name, copyfrom, len)) {
                                        magic |= pathspec_magic[i].bit;
                                        break;
                                }
                                if (!prefixcmp(copyfrom, "prefix:")) {
                                        char *endptr;
                                        pathspec_prefix = strtol(copyfrom + 7,
                                                                 &endptr, 10);
                                        if (endptr - copyfrom != len)
                                                die(_("invalid parameter for pathspec magic 'prefix'"));
                                        /* "i" would be wrong, but it does not matter */
                                        break;
                                }
                        }
                        if (ARRAY_SIZE(pathspec_magic) <= i)
                                die(_("Invalid pathspec magic '%.*s' in '%s'"),
                                    (int) len, copyfrom, elt);
                }
                if (*copyfrom != ')')
                        die(_("Missing ')' at the end of pathspec magic in '%s'"), elt);
                long_magic_end = copyfrom;
                copyfrom++;
        } else {
                /* shorthand */
                for (copyfrom = elt + 1;
                     *copyfrom && *copyfrom != ':';
                     copyfrom++) {
                        char ch = *copyfrom;

                        if (!is_pathspec_magic(ch))
                                break;
                        for (i = 0; i < ARRAY_SIZE(pathspec_magic); i++)
                                if (pathspec_magic[i].mnemonic == ch) {
                                        short_magic |= pathspec_magic[i].bit;
                                        break;
                                }
                        if (ARRAY_SIZE(pathspec_magic) <= i)
                                die(_("Unimplemented pathspec magic '%c' in '%s'"),
                                    ch, elt);
                }
                if (*copyfrom == ':')
                        copyfrom++;
        }

        magic |= short_magic;
        *p_short_magic = short_magic;

        if (pathspec_prefix >= 0 &&
            (prefixlen || (prefix && *prefix)))
                die("BUG: 'prefix' magic is supposed to be used at worktree's root");

        if (pathspec_prefix >= 0) {
                match = xstrdup(copyfrom);
                prefixlen = pathspec_prefix;
        } else if (magic & PATHSPEC_FROMTOP) {
                match = xstrdup(copyfrom);
                prefixlen = 0;
        } else {
                match = prefix_path_gently(prefix, prefixlen, &prefixlen, copyfrom);
                if (!match)
                        die(_("%s: '%s' is outside repository"), elt, copyfrom);
        }
        *raw = item->match = match;
        /*
         * Prefix the pathspec (keep all magic) and assign to
         * original. Useful for passing to another command.
         */
        if (flags & PATHSPEC_PREFIX_ORIGIN) {
                struct strbuf sb = STRBUF_INIT;
                const char *start = elt;
                if (prefixlen && !limit_pathspec_to_literal()) {
                        /* Preserve the actual prefix length of each pattern */
                        if (long_magic_end) {
                                strbuf_add(&sb, start, long_magic_end - start);
                                strbuf_addf(&sb, ",prefix:%d", prefixlen);
                                start = long_magic_end;
                        } else {
                                if (*start == ':')
                                        start++;
                                strbuf_addf(&sb, ":(prefix:%d)", prefixlen);
                        }
                }
                strbuf_add(&sb, start, copyfrom - start);
                strbuf_addstr(&sb, match);
                item->original = strbuf_detach(&sb, NULL);
        } else
                item->original = elt;
        item->len = strlen(item->match);
        item->prefix = prefixlen;

        if ((flags & PATHSPEC_STRIP_SUBMODULE_SLASH_CHEAP) &&
            (item->len >= 1 && item->match[item->len - 1] == '/') &&
            (i = cache_name_pos(item->match, item->len - 1)) >= 0 &&
            S_ISGITLINK(active_cache[i]->ce_mode)) {
                item->len--;
                match[item->len] = '\0';
        }

        if (flags & PATHSPEC_STRIP_SUBMODULE_SLASH_EXPENSIVE)
                for (i = 0; i < active_nr; i++) {
                        struct cache_entry *ce = active_cache[i];
                        int ce_len = ce_namelen(ce);

                        if (!S_ISGITLINK(ce->ce_mode))
                                continue;

                        if (item->len <= ce_len || match[ce_len] != '/' ||
                            memcmp(ce->name, match, ce_len))
                                continue;
                        if (item->len == ce_len + 1) {
                                /* strip trailing slash */
                                item->len--;
                                match[item->len] = '\0';
                        } else
                                die (_("Pathspec '%s' is in submodule '%.*s'"),
                                     elt, ce_len, ce->name);
                }

        if (limit_pathspec_to_literal())
                item->nowildcard_len = item->len;
        else {
                item->nowildcard_len = simple_length(item->match);
                if (item->nowildcard_len < prefixlen)
                        item->nowildcard_len = prefixlen;
        }
        item->flags = 0;
        if (item->nowildcard_len < item->len &&
            item->match[item->nowildcard_len] == '*' &&
            no_wildcard(item->match + item->nowildcard_len + 1))
                item->flags |= PATHSPEC_ONESTAR;

        /* sanity checks, pathspec matchers assume these are sane */
        assert(item->nowildcard_len <= item->len &&
               item->prefix         <= item->len);
        return magic;
}

static int pathspec_item_cmp(const void *a_, const void *b_)
{
        struct pathspec_item *a, *b;

        a = (struct pathspec_item *)a_;
        b = (struct pathspec_item *)b_;
        return strcmp(a->match, b->match);
}

static void NORETURN unsupported_magic(const char *pattern,
                                       unsigned magic,
                                       unsigned short_magic)
{
        struct strbuf sb = STRBUF_INIT;
        int i, n;
        for (n = i = 0; i < ARRAY_SIZE(pathspec_magic); i++) {
                const struct pathspec_magic *m = pathspec_magic + i;
                if (!(magic & m->bit))
                        continue;
                if (sb.len)
                        strbuf_addstr(&sb, " ");
                if (short_magic & m->bit)
                        strbuf_addf(&sb, "'%c'", m->mnemonic);
                else
                        strbuf_addf(&sb, "'%s'", m->name);
                n++;
        }
        /*
         * We may want to substitute "this command" with a command
         * name. E.g. when add--interactive dies when running
         * "checkout -p"
         */
        die(_("%s: pathspec magic not supported by this command: %s"),
            pattern, sb.buf);
}

/*
 * Given command line arguments and a prefix, convert the input to
 * pathspec. die() if any magic in magic_mask is used.
 */
void parse_pathspec(struct pathspec *pathspec,
                    unsigned magic_mask, unsigned flags,
                    const char *prefix, const char **argv)
{
        struct pathspec_item *item;
        const char *entry = argv ? *argv : NULL;
        int i, n, prefixlen;

        memset(pathspec, 0, sizeof(*pathspec));

        if (flags & PATHSPEC_MAXDEPTH_VALID)
                pathspec->magic |= PATHSPEC_MAXDEPTH;

        /* No arguments, no prefix -> no pathspec */
        if (!entry && !prefix)
                return;

        if ((flags & PATHSPEC_PREFER_CWD) &&
            (flags & PATHSPEC_PREFER_FULL))
                die("BUG: PATHSPEC_PREFER_CWD and PATHSPEC_PREFER_FULL are incompatible");

        /* No arguments with prefix -> prefix pathspec */
        if (!entry) {
                static const char *raw[2];

                if (flags & PATHSPEC_PREFER_FULL)
                        return;

                if (!(flags & PATHSPEC_PREFER_CWD))
                        die("BUG: PATHSPEC_PREFER_CWD requires arguments");

                pathspec->items = item = xmalloc(sizeof(*item));
                memset(item, 0, sizeof(*item));
                item->match = prefix;
                item->original = prefix;
                item->nowildcard_len = item->len = strlen(prefix);
                item->prefix = item->len;
                raw[0] = prefix;
                raw[1] = NULL;
                pathspec->nr = 1;
                pathspec->_raw = raw;
                return;
        }

        n = 0;
        while (argv[n])
                n++;

        pathspec->nr = n;
        pathspec->items = item = xmalloc(sizeof(*item) * n);
        pathspec->_raw = argv;
        prefixlen = prefix ? strlen(prefix) : 0;

        for (i = 0; i < n; i++) {
                unsigned short_magic;
                entry = argv[i];

                item[i].magic = prefix_pathspec(item + i, &short_magic,
                                                argv + i, flags,
                                                prefix, prefixlen, entry);
                if (item[i].magic & magic_mask)
                        unsupported_magic(entry,
                                          item[i].magic & magic_mask,
                                          short_magic);

                if ((flags & PATHSPEC_SYMLINK_LEADING_PATH) &&
                    has_symlink_leading_path(item[i].match, item[i].len)) {
                        die(_("pathspec '%s' is beyond a symbolic link"), entry);
                }

                if (item[i].nowildcard_len < item[i].len)
                        pathspec->has_wildcard = 1;
                pathspec->magic |= item[i].magic;
        }


        if (pathspec->magic & PATHSPEC_MAXDEPTH) {
                if (flags & PATHSPEC_KEEP_ORDER)
                        die("BUG: PATHSPEC_MAXDEPTH_VALID and PATHSPEC_KEEP_ORDER are incompatible");
                qsort(pathspec->items, pathspec->nr,
                      sizeof(struct pathspec_item), pathspec_item_cmp);
        }
}

/*
 * N.B. get_pathspec() is deprecated in favor of the "struct pathspec"
 * based interface - see pathspec.c:parse_pathspec().
 *
 * Arguments:
 *  - prefix - a path relative to the root of the working tree
 *  - pathspec - a list of paths underneath the prefix path
 *
 * Iterates over pathspec, prepending each path with prefix,
 * and return the resulting list.
 *
 * If pathspec is empty, return a singleton list containing prefix.
 *
 * If pathspec and prefix are both empty, return an empty list.
 *
 * This is typically used by built-in commands such as add.c, in order
 * to normalize argv arguments provided to the built-in into a list of
 * paths to process, all relative to the root of the working tree.
 */
const char **get_pathspec(const char *prefix, const char **pathspec)
{
        struct pathspec ps;
        parse_pathspec(&ps,
                       PATHSPEC_ALL_MAGIC & ~PATHSPEC_FROMTOP,
                       PATHSPEC_PREFER_CWD,
                       prefix, pathspec);
        return ps._raw;
}

void copy_pathspec(struct pathspec *dst, const struct pathspec *src)
{
        *dst = *src;
        dst->items = xmalloc(sizeof(struct pathspec_item) * dst->nr);
        memcpy(dst->items, src->items,
               sizeof(struct pathspec_item) * dst->nr);
}

void free_pathspec(struct pathspec *pathspec)
{
        free(pathspec->items);
        pathspec->items = NULL;
}